Apparatus for cooling a stress sensitive continuous casting

ABSTRACT

An apparatus for cooling a stress sensitive continuous casting emerging from a mold. The apparatus is particularly applicable to aluminum base alloys when cast in the horizontal mode. The apparatus includes means for applying a first cooling medium to an outer surface of the mold and the emergent portion of the casting; means for removing the first cooling medium from the casting; means spaced from the removing means for applying a second cooling medium to the casting; and means for removing the second cooling medium.

United States Patent 1191 Dore et al. 1 1 *Nov. 6, 1973 [54] APPARATUS FOR COOLING A STRESS 2,754,556 7/1956 Kilpatrick 164/89 SENSITIVE CONTINUOUS CASTING X azc c e a 1 Inventors: James E- Dore, Milford, 3,598,173 8/1971 Dore et 31.. 164/283 x William O. Stauffer, Woodfield, 3,463,220 8/1969 Moritz 1 164/89 X Ohio 2,698,467 l/1955 Tarquinec et a1, 164/89 2,789,327 4 1957 C l 164 89 UX [73] Assignee: Olin Corporation, New Haven, or Cy Conn, Primary ExaminerRobert D. Baldwin I 1 Nonce' t t g of ft k l g lgsg Att0rney-Paul Weinstein, Robert H. Bachman and pa en su sequen 0 ug. G d M has been disclaimed. or on enzles [22] Filed: Mar. 19, 1971 57 ABSTRACT [21] Appl. No.: 126,130 1 Related U 5 Application Data An apparatus for cooling a stress sensitive continuous fs 768 354 O t 17 1968 P t casting emerging from a mold. The apparatus is partic- 3 22 3; c a ularly applicable to aluminum base alloys when cast in the horizontal mode. The apparatus includes means for applying a first cooling medium to an outer surface of the mold and the emergent portion of the casting; [58] 164/89 283 means for removing the first cooling medium from the m casting; means spaced from the removing means for applying a second cooling medium to the casting; and [56] uNlTE g s g zi gs gg rENTs means for removing the second cooling medium.

2,564,337 8/1951 Maddex 164/283 X 13'Claims, 2 Drawing Figures /Z/ 3; /Z4 W PAIENTEU NOV 6 i975 SHEET 10F 2 INVENTORS JAMES E. DORE WILL/AM O. STAUFFER m/g ATTORNEY PAIENIEDNW 6 ma 7 3.770.046 SHEET 2 BF 2 INVENTORS BY Z i" JAMES E. DORE WILLIAM G $774UFFER MN .H w, Mm F. 0 Wm kN NR w x ATTORNEY APPARATUS FOR COOLING A STRESS SENSITIVE CONTINUOUS CASTING This application is a division of U.S. application Ser. No. 768,354, filed Oct. 17, 1968, now U.S. Pat. No. 3,598,173 issued Aug. 10, 1971.

Most of the present day wrought aluminum alloy products (sheet, extrusions, wire and forgings) are made from process billet produced by vertical direct chill casting operations. However, considerable amounts of scrap are generated in the casting of alloy billet due to gross surface defects that must be removed by scalping. Also, it is difficult to cast small cross section alloy billet in the DC operation. Production rates are low and conversion costs are high.

Billet of small cross section can be made continuously on Properzi casting machines, as described, for example, in U.S. Pat. No. 2,710,433. However, at the present time, product availability from Properzi machines is limited and high quality cannot be made in alloys such as 5356, 4043, 6061, and other industrial wire alloys.

A modified Tessman casting process, as described, for example, in U.S. Pat. No. 2,837,791, can be used to continuously cast 2-% inch diameter rod in Electrical Conductive grade and 5005 alloys. However, because of heat transfer considerations inherent in the design and the action of the reciprocating mold, highlyalloyed product cannot be cast with this process.

Other horizontal casting processes are limited because of less than desirable internal or surface quality of the billet. Billet of medium alloy content can be cast with the Ugine process, as described, for example in REVUE DE LALUMINUM, Vol. 34 (1957) No. 244, p. 624-627, but the casting rates are low. The cast billet must be large in cross section to reduce scrap losses during scalping and the cost of the finished product is about equal to that of the vertical DC casting process.

Furthermore, for a given alloy, a given amount of super heat (casting temperature), a given casting speed, and a given amount of cooling fluid applied to the mold, there is a given mold length that will produce billet of optimum surface quality and smoothness. However, this ideal length is different if any, or all, of these variables are changed. Thus, it is important to be able to vary the mold length to adjust to these varied conditions and obtain optimum surface quality and smoothness.

Furthermore, the mold length is preferably different during start-up than during the rest of the casting operation. With the mold arrangement of the present invention, after start-up has taken place, the mold assembly can be moved to obtain the desired mold length for the given alloy, super heat and cooling condition while casting continues 'to obtain optimum surface quality.

It is an object of the present invention to provide a casting apparatus whereby a variety of aluminum alloy systems may be continually cast.

It is-another object of the present invention to cast a variety of alloy systems in a variety of sizes.

It is another object of the present invention to provide apparatus casting a variety of alloy systems in a variety of sizes at high casting speed.

it is another object of the present invention to produce continuous castings having such a sufficiently fine quality of surface that no scalping or other surface treatment is necessary prior to hot working the casting.

It is still another object of the present invention to produce a continuous casting having a sound internal metallurgical structure.

It is still another object of the present invention to provide an apparatus wherein the mold length may be varied for different alloys and may be varied while the casting machine is being operated.

It is still another object of the present invention to provide apparatus at a cost as low as or lower than the methods and apparatus presently available.

It is still another object of the present invention to provide apparatus which will insure that the cast bar will be straight.

Other objects and advantages will become apparent from the following description and drawings, in which:

FIG. 1 is a sectional view of a portion of the continuous casting apparatus of the present invention;

FIG. 2 is a sectional view illustrating modifications of the present invention.

The casting machine of the present invention consists of the following basic parts.

As shown in FIG. 1, there is provided a metal holding unit 10, such as, for instance, a feed box having an insulating lining 12 made of, for example, marinite. The feed nozzle insert 412 is placed in abutment with the holding unit 10, separated therefrom by gaskets 10a and 10b. The feed nozzle 40 is supported on an adjustable Vee block 30 mounted on the bed of the machine. The Vee block has an upper portion 31 and a lower portion 32 with the upper and lower portions being held together in a tight fit around the feed nozzle by means of bolts 33.

The mold assembly consists of a bearing block 51 which may be of one or two pieces, but a two-piece design is preferred because of ease of assembly and disassembly, a drive sprocket 58, and a mold 20. Bolts 52 hold these parts in engagement. As shown FIG. 1 also illustrates an embodiment of the mold and cooling water application structure.

In'this embodiment, cooling water is introduced into the chamber 601 of mold spray box 607 by means of conventional couplings 602 known to those skilled in the art. From the spray box, the cooling water passes through a circumferential baffle in the spray box containing a series of holes 603 into a second chamber 604. A plate- 605 is affixed to mold spray box 607 by means of fasteners 606. However, it is to be noted that there is a step 608 on the plate 605 resulting in clearance of from 13 to 50 thousandths of an inch, preferably 15 to 25 thousandths, between the plate and the lower portion of the spray box 607. Thus, the cooling water passes in a continuous sheet from chamber 604 between the plate 605 and the spray box 607 contacts first the mold plate 103 and then the mold 20. It then follows the mold contour and exits from the billet surface at 105 at an angle of from 3 to 20 to the surface of thecasting. An angle of 3 to 10 between the cooling water and the casting at the point of contact is preferred for most applications.

It can also be seen from FIG. 1 that the mold plate 103 contacts cam followers 124 which are journaled on the pins 121. Nuts hold the pins firmly in place within the fixed support 125, which is appropriately affixed to the mold spray box in a conventional manner such as by fasteners or by welding. Thus, the mold plate and the cam followers rotate and the mold spray box remains stationary.

As shown in FIG. 1, after the casting emerges from the mold, wiping and cooling arrangements are provided within a splash chamber. Within this chamber, there is provided a mechanical wiper 710. This wiper includes one or more gaskets 711. In the case of 2-% inch diameter cast bar, 2 inch size gaskets are used to provide effective wiping action and good contact with the casting 3. These gaskets are mounted in a holder 712 which, in turn, is held in the wiper housing 713 with conventional fasteners such as nut-and-bolt arrangement 714.

Adjacent the mechanical wiper 710 is an air wiper 720. The air wiper 720 comprises a header section 721 which surrounds the casting circumferentially and a plurality of nozzles 720 through which the air passes at an angle of 30 to 60, preferably 45, with respect to a plane passing through the header. The size of the nozzles may be a slot orifice of 0.045 inch. The number of orifices 722 may vary, for example, from three to 20, but it is preferred to have from six to eight orifices. An air pressure of, for example, 100 psi is applied through a suitable conduit 723 from a pump, not shown. The purpose of the air wiper is to remove any water from the surface of the bar that gets by the mechanical wipers.

Additional cooling may be provided if desired and, in fact, is necessary in the casting of certain stress sensitive alloys. Such additional cooling may be provided at a secondary cooling station 730. The secondary cooling station is simple in construction. There is provided a housing or header 731 into which a cooling medium, for example, water, is introduced through conduit 732. A plurality of drilled holes 733 are provided which are quite close to the casting. The angle between the surface of the casting and the drilled holes 733 may be from to 45, preferably 30". The number of such holes should be between 15 and 45, preferably to 30. The diameter of such holes must be from onesixteenth to five-thirtyseconds inch, for example, threethirtyseconds inch diameter may be used. The water may be applied at a rate of 10 to 100 gallons per minute, depending on casting speed and the alloy and size of bar being cast. Upon leaving the secondary cooling station 730, the secondary cooling water may beremoved with additional wipers such as shown at 740, held in place with support 741 and fasteners 742. If desired, an additional air wiper such as shown at 720 may also be provided. Also, if desired, the mechanical wipers and/or air wiper may be replaced with a water wiper which directs a continuous sheet of water up the bar in a direction opposite to the direction of bar travel. The sheet of water issuing from the water wiper should make an angle of between 15 and 45 with the bar surface. The flow rate of water issuing from the water wiper is determined by the amount of water being applied to the surface at the bar by the secondary cooling station. Water flow from the wiper is adjusted so that no water exits the splash chamber or encloses down the bar.

Another embodiment of the invention is shown in FIG. 2. Much of the embodiment shown in FIG. 2 is essentially the same as that shown in FIG. 1.

As was previously described, molten metal to be cast trough 1 in communication with a furnace or large reservoir of molten alloy.

Cooling water is supplied to the mold 20 by introduction of the cooling water into spray box 111. In this embodiment, the spray box directs the cooling medium in a direction parallel to the movement of the casting but in an opposite direction to the casting movement. The mold surface 21 then turns the cooling fluid and directs it onto the casting 3 at an angle from 3 to 20 to the surface of the casting, preferably 3 to 10.

In FIG. 2, the cooling water is shown introduced in a direction parallel but opposite to the direction of travel of the mold. In FIG. 1, the cooling water is introduced perpendicular to the direction of travel of the mold. Thus, it is apparent that the cooling water may be introduced at any convenient angle with respect to the movement of the casting, so long as the mold contour is such as to direct the cooling water to contact the castings as it emerges from the mold at an angle from 3 to 20 to the surface of the casting, preferably 3 to 10.

If desired, additional cooling of the ingot may be provided through the use of header 141 and super-quench nozzles 142 (U.S. Pat. No. 3,323,577) which are placed within cooling chamber 13. At the entrance to the cooling chamber, means for wiping the casting may be provided at 15, for instance, rubber wipers 151 may be provided affixed into holders 152 by conventional fasteners. An additional rubber wiper 16 may be provided as the casting exits from chamber 13.

The drive mechanism for the withdrawal mechanism is similar to that shown in FIG. 1. The drive sprocket which imparts the motion to the chain 61 may be of the simple bicycle sprocket type (not shown) with teeth thereon which engage the feet 61. This type of sprocket-and-chain arrangement is conventional and forms no part of the present invention, except insofar as it is in combination with the feet 61 and other casting apparatus of the present invention.

Finally, ultra-sonic testing equipment, shown schematically at 980, known in the art, may be used in testing the soundness of the casting after the casting has been removed from the mold, coolant removal section, and secondary cooling removal section. Such testing of the soundnessof metallurgical products, such as bar stock, is known in the art and forms no part of the present invention, except insofar as it is combined with the casting process and apparatus of the present invention.

It is to be understood that the invention is not limited to the illustrations described and shown herein which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modifications of form, size, arrangement of parts and detail of operation, but rather is intended to encompass all such modifications which are within the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. An apparatus for cooling a stress sensitive continuous casting emerging in a substantially horizontal direction, from a mold, comprising:

A. a first coolant applying means for applying a first cooling medium in a continuous circumferential sheet to an outer surface of the mold and the emerging portion of the casting;

B. a first coolant removing means, spaced from said first coolant applying means in the direction of the casting movement, for removing substantially all of said first cooling medium from said casting;

C. means to expose the casting to the ambient atmosphere;

D. a second coolant applying means spaced from said first coolant removing means in the direction of the movement, for applying a second cooling medium to said casting after exposure to said ambient atmosphere; and

E. a second coolant removing means spaced from said second coolant applying means in the direction of the casting movement for removing said cooling medium from said casting.

2. An apparatus as in claim 1 in which the means for applying said first cooling medium comprises a spray box having a circumferential baffle, said circumferential baffle having a plurality of openings therein.

3. An apparatus as in claim 2 in which said spray box is provided with a plate affixed to said spray box, said plate being so shaped as to regulate the direction and pressure of applied cooling medium.

4. An apparatus as in claim 3 in which said plate has a portion of reduced thickness which regulates said first cooling medium.

5. An apparatus as in claim 4 in which said spray box contains a circumferential header in addition to said bafi'le.

6. An apparatus as in claim 5 wherein said means for removing said first cooling medium comprises: at least one rubber wiper adapted to contact the periphery of the casting, said wiper being held in position by at least one holder, means for supporting said holder so that said wiper can engage the periphery of said casting.

7. An apparatus as in claim 6 in which a plurality of wipers are provided.

8. An apparatus as in claim 7 further including a concentric tube having a plurality of orifices and means for introducing a gas under pressure into said tube whereby said gas exits from said orifices to remove said first cooling medium not removed by said wiper.

9. An apparatus as in claim 8 in which the orifices are at an angle of 30 to 60 with respect to a plane passing through said concentric tube.

10. An apparatus as in claim 9 in which said wipers, said concentric tube, and said means for applying said second cooling means are positioned within a chamber.

11. An apparatus as in claim 10 wherein said means for applying said second cooling medium to said casting comprises: a header; means for introducing a cooling medium into said header; said header having a plurality of openings therein for applying said second cooling medium to said casting.

12. An apparatus as in claim 11 wherein said openings are at an angle of 15 to 45 with respect to the surface of the casting.

13. An apparatus as in claim 12 wherein said means for removing said second cooling medium comprises at least one rubber wiper contacting the periphery of said casting, said wiper being held in position by at least one holder; and means for supporting said holder so that said wiper can engage the periphery of said casting. 

1. An apparatus for cooling a stress sensitive continuous casting emerging in a substantially horizontal direction, from a mold, comprising: A. a first coolant applying means for applying a first cooling medium in a continuous circumferential sheet to an outer surface of the mold and the emerging portion of the casting; B. a first coolant removing means, spaced from said first coolant applying means in the direction of the casting movement, for removing substantially all of said first cooling medium from said casting; C. means to expose the casting to the ambient atmosphere; D. a second coolant applying means spaced from said first coolant removing means in the direction of the movement, for applying a second cooling medium to said casting after exposure to said ambient atmosphere; and E. a second coolant removing means spaced from said second coolant applying means in the direction of the casting movement for removing said cooling medium from said casting.
 2. An apparatus as in claim 1 in which the means for applying said first cooling medium comprises a spray box having a circumferential baffle, said circumferential baffle having a plurality of openings therein.
 3. An apparatus as in claim 2 in which said spray box is provided with a plate affixed to said spray box, said plate being so shaped as to regulate the direction and pressure of applied cooling medium.
 4. An apparatus as in claim 3 in which said plate has a portion of reduced thickness which regulates said first cooling medium.
 5. An apparatus as in claim 4 in which said spray box contains a circumferential header in addition to said baffle.
 6. An apparatus as in claim 5 wherein said means for removing said first cooling medium comprises: at least one rubber wiper adapted to contact the periphery of the casting, said wiper being held in position by at least one holder, means for supporting said holder so that said wiper can engage the periphery of said casting.
 7. An apparatus as in claim 6 in which a plurality of wipers are provided.
 8. An apparatus as in claim 7 further including a concentric tube having a plurality of orifices and means for introducing a gas under pressure into said tube whereby said gas exits from said orifices to remove said first cooling medium not removed by said wiper.
 9. An apparatus as in claim 8 in which the orifices are at an angle of 30* to 60* with respect to a plane passing through said concentric tube.
 10. An apparatus as in claim 9 in which said wipers, said concentric tube, and said means for applying said second cooling means are positioned within a chamber.
 11. An apparatus as in claim 10 wherein said means for applying said second cooling medium to said casting comprises: a header; means for introducing a cooling medium into said header; said header having a plurality of openings therein for applying said second cooling medium to said casting.
 12. An apparatus as in claim 11 wherein said openings are at an angle of 15* to 45* with respect to the surface of the casting.
 13. An apparatus as in claim 12 wherein said means for removing said second cooling medium comprises at least one rubber wiper contacting the periphery of said casting, said wiper being held in position by at least one holder; and means for supporting said holder so that said wiper can engage the periphery of said casting. 